Fun Fact #3: G-code Files Are Just Text — You Can Read, Hack, and Troll With Them

“I thought it was a program. Turns out, it’s poetry.”

✨ Introduction: The Language Your Printer Actually Speaks

You might imagine G-code as some obscure mechanical incantation only decipherable by seasoned engineers. But here’s the twist — it’s just plain text.

Seriously. Open it with Notepad, VS Code, or any basic text editor, and you'll see line after line of readable commands. This simplicity is what makes G-code so powerful, customizable… and yes, prone to creative abuse.

📂 What Is G-code Really?

G-code is the instruction set your 3D printer reads line-by-line. It tells the printer:

where to go
how fast to move
when to heat up
and when to cool down, extrude, or wait

Think of it as a screenplay for your printer — a mechanical monologue.

✅ Example Basic Command:

Move to X=10mm, Y=20mm, Z=0.2mm at a speed of 1500mm/min.

🛠️ Practical Tweaks You Can Try

🎯 Want to prime the nozzle before starting a print?

🌀 Want your printer to do a spin before printing?

💬 Want to display a cool message on the LCD?

⚠️ What Not to Do With G-code

While G-code is easy to edit, it’s also easy to break things if you’re careless:

❌ Delete G28 (auto-home)?
Goodbye home position, hello chaos.
❌ Forget G92 E0 before extruding?
You might over-extrude or retract endlessly.
❌ Spam M300?
Your printer will beep — possibly in Morse — and you’ll regret everything.

😎 Sass Mode: G-code Writes the Symphony

G-code is your printer’s script.
Write it well — it performs a flawless ballet.
Write it poorly — it throws a molten tantrum on your print bed.

📘 Want to Dive Deeper?

Explore our Beginner’s Guide to G-code, where we cover:

What each command does
How to modify startup and end G-code
Safe testing methods
Real examples from live print jobs

→ Read the G-code Beginner’s Guide

📑 Appendix: G-code Command Cheat Sheet

Command	Meaning	Common Use / Notes
`G28`	Auto-home	Essential before every print
`G1`	Linear move	Core command for movement
`G92`	Set position	Often used for extruder reset
`G90`	Absolute positioning	Default for most printers
`G91`	Relative positioning	Used for incremental moves
`M104`	Set nozzle temp (no wait)	Quick heat-up
`M109`	Set nozzle temp and wait	Preheat before printing
`M140`	Set bed temp (no wait)	Preheats bed
`M190`	Set bed temp and wait	Waits for bed to heat up
`M106`	Turn fan on	`S255` = full speed
`M107`	Turn fan off	Shuts down cooling fan
`M117`	LCD message	Display custom text
`M300`	Beep / sound	Beeps printer speaker
`M82`	Set extruder to absolute mode	Works with `G90`
`M83`	Set extruder to relative mode	Good for purge scripts
`G2`/`G3`	Arc moves (clockwise/counter)	Not supported on all printers
`G29`	Auto bed leveling	For printers with sensors (BLTouch, etc.)
`G34`	Z-axis auto alignment	Advanced feature for multiple Z-motor printers
`M501`	Load EEPROM settings	Reads saved values
`M500`	Save settings to EEPROM	Use after config changes

🔧 Starter Code Example

👀 Pro Tip:

Different firmware (Marlin, Klipper, RepRap) may interpret or support different commands. Always consult your printer’s official docs before experimenting.

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